text: *Bulk Fe. Cast iron, consisting of scrap iron of construction grade, has been used as a reactive material for permeable reactive barriers for groundwater remediation. Reactions are generally believed to occur on the Fe (oxide) surface; however, graphite inclusions have been shown can also serve as a reaction sites.
  *Nanoscale Fe. In addition to using macroscale iron in PRBs, nanoparticles (1-100 nm diameter)  of zerovalent iron (nZVI) are effective.
  *Zn. Zinc has showed much higher reactivity toward pentachlorophenol than iron. This indicates that zinc may be used as a replacement for ZVI in dechlorinating chlorinated phenols. Chlorinated phenols are sequentially dechlorinated and thus less chlorinated phenols have been identified as a reduction product.